Apparatus for heating fluids



Aug. 5, 1958 H. F. PAYNE ETAL APPARATUS FOR HEATING FLUIDS 6Sheets-Sheet 1 Filed March 16, 1955 \w &\ Mm

HUGH FREDERICK PAYNE 8 FREDERICK WALTER BAUER BY Aug 5, 1958 H. F. PAYNEETAL APPARATUS FOR HEATING mums e Sheets-Sheet 2 Filed March 16, 1955 IN V EN TORSa HUGH FREDERICK PAYNE FREDERICK WALTER BAUER BY WWW/ 4M 5,1958 H. F. PAYNEETAL 2,845,907

APPARATUS FOR HEATING FLUIDS Filed March 16, 1955 6 Sheets-Sheet 3INVENTORJ. 1 HUGH FREDERICK PAYNE a 4 FREDERICK WALTER BAUER Aug. 5,1958 H. F. PAYNE ETAL 2,845,907

APPARATUS FOR HEATING FLUIDS 6 Sheets-Sheet 4 Filed March 16, 1955 FIG.4.

INVENTORS. HUGH FREDERICK PAYNE a FREDERICK WALTER BAUER BY WeTTOIQNEYS.

5, 1958 H. F. PAYNE EIAL 2,845,907

APPARATUS FOR HEATING FLUIDS Filed March 16, 1955 e Sheets-Sheet 5INVENTORS. HUGH FREDERICK PAYNE 8 FREDERICK WALTER BAUER I I I O I I//I/ I 1958 H. F. PAYNE ETAL 2,845,907

APPARATUS FOR HEATING FLUIDS 6 Sheets-Sheet 6 Filed March 16, 1955 FIG.6.

INVENTORS. HUGH FREDERICK PAYNE FREDERICK WALTER BAUER BY United StatesPatent APPARATUS FOR HEATING FLUIDS Hugh Frederick Payne, London, andFrederick Walter Bauer, South Croydon, England, assignors to John B.Pierce Foundation, New Haven, Conn, a corporation of New YorkApplication March 1 6, 1955, Serial No. 494,645

Claims priority, application Great Britain March 22, 1954 4 Claims. (Cl.122-275) This invention relates to apparatus for heating fluids and,more particularly, pertains to improved heat transfer structure forefficiently and uniformly heating temperature sensitive fluids.

' In heat transfer systems in which a temperature sensitive fluid isheated, care must be exercised to insure that the temperature of thefluid is not raised above a predetermined level at any point in thesystem, in order to prevent deterioration of such fluid. However,previously known heat transfer systems provided continuous heating pipescarrying the fluid which tended to substantially isolate certain fluidportions for an extended distance along the pipe, this arrangementpermitting localized heating and excessive fluid temperatures.Accordingly, it is an object of the present invention to provide a heattransfer system in which fluids may be uniformly and efficiently heatedWithout excessively heating any localized portions of such fluid.

It is another object of the invention to provide heat transfer systemsof the above character in which the fluid to be heated is thoroughlymixed one or more times during its circulation through pipe sections topreclude the excessive heating of any portion of the fluid.

It is a further object of the invention to provide heating systems ofthe above character in which the fluid in adjacent pipe sections travelsin opposite directions in order to provide for more uniform andeflicient fluid heating.

It is still a further object of the invention to provide heat transferstructure formed by an enclosure whose interior walls are at leastpartially covered by sectionalized panels of pipes in which the fluidtravels in opposite directions in adjacent sections, and a passageleading from the enclosure in which further fluid carrying pipes aredisposed and heated by gases escaping from the enclosure.

These and further objects of the present invention are accomplished bycirculating the fluid to be heated in one or more sectionalized panelsof adjacent parallel pipes in which the fluid in traversing the panel orpanels sequentially travels in opposite directions in adjacent sections,the panels preferably being heated by radiant heat.

In a preferred embodiment of the invention, the panels form at leastpart of the interior surface of an enclosure containing the heat source,a plurality of panels being joined in order to uniformly and eflicientlyheat the circulating fluid. Preferably, further pipes carrying the fluidcirculated through the panels are disposed in an outlet passagecommunicating with the enclosure in order to extract heat from the hotgases escaping from the heat source found in the enclosure.

These and further objects and advantages of the present invention willbe more readily understood when the following description is read inconnection with the accompanying drawings in which:

Figure 1 is a plan view, partially broken away, of heat transferapparatus constructed in accordance with the principles of the presentinvention;

Figure 2 is a longitudinal section of the apparatus shown in Figure 1taken on the view line 2-2 looking in the direction of the arrows;

Figure 3 is another longitudinal section of the heat' in the directionof the arrows;

Figure 5 is another transverse section of the heat transfer apparatustaken on the view line 55 of Figure 1 looking in the direction of thearrows; and

Figure 6 is yet another transverse section of the heat transferapparatus taken on the view line 66 of Figure 1' looking in thedirection of the arrows.

Referring to an illustrative embodiment of the invention in greaterdetail with particular reference to the drawings, a box-like structureis formed of a floor 10, a roof 11, sides 12 and 13, a front wall 14 anda rear wall 15, each of these members preferably being formed of one ormore layers of fire brick or similar heat resistant materials which willalso preferably insulate the entire structure. In order to provide astrong rigid assembly, suitably positioned reinforcing channels 16 maybe disposed on the members 11 to 15, inclusive. To provide access to theinterior of the structure, openings 17 and 18 are provided in the frontand rear walls 14 and 15, respectively, and closed by covers 19 and 20,respectively.

Suitably positioned on the floor is a heater 21 having three angledsurfaces 22 with a plurality of openings 23 to permit the burning of oilor a gas mixture entering through an inlet 24, broken away for clarity.The flames at the openings 23 provide a uniform source of radiant heateffectively heating various elements explained in detail below.Obviously, other equivalent heaters fired by oil or by electrical means,for example, could be used in place of the gas heater 21.

As best shown in Figures 3 and 5, a panel 25 formed of a plurality ofadjacently mounted parallel pipes 26 substantially covers the sides andforms a rear wall 25a of what will be termed an enclosure 27. In orderto provid a substantially solid metallic wall to the radiant heat fromthe heater 21, diametrically opposed fins 28 are r formed on the pipes26 and are closely spaced as clearly shown in Figure 5. However, thepipes 26 forming a lower portion of the rear wall 25a do not have thefins 28 mounted thereon, except at points near their extremities, inorder to permit the hot gases generated by the heater 21 to escape pastthe wall 25a into a passage 30 and out a flue 31 in the roof 11 (Figure2).

The pipes 26 communicate at their ends with headers 32 and 33 onopposite sides of the front wall 14, best shown in Figures 3 and 4, theheader 32 being joined to a fluid inlet duct 34. A partition 35 (Figure4) divides the header 32 into two substantially independent sectionseach having a number of the pipes 26 dictated by the particularstructure. Thus, if the panel 25 was used independently, the sectionswould preferably be substantially equal. However, in this instance thereare ten pipes in the lower section and five pipes in the upper sectionto equalize fluid circulation in a manner explained hereinafter. Ifdesired, small vent holes 36 may be formed in the partition 35 to permitgases to flow therethrough. A number of vents 37 are also suitablypositioned on the headers 32 and 33 and serve to remove gases found inthe circulating fluids.

Any suitable means may be employed to support the panel 25 such asbrackets 38 and 39 fastened in the sides 12 and 13, respectively. Itshould also be understood that the pipes 26 may be closely spacedtogether in which case the fins 28 would be unnecessary. In this event,the lower pipes could be spaced in 'order' to permit the escape of gasesto the passage 30.

Substantially covering the interior surface of the roof of'the enclosure27 are two panels 40 and 41 (Figure 1) formed of adjacent parallel pipes42 and 43, respectively. Diametrically opposed fins 44 and 45 may beprovided on the pipes 42 and 43, respectively, for the same purpose asthe fins 28 used on the pipes 26. At their forward end, the pipes 42 and43 are joined to a header 46, extending across the front end of the roof11 and sectionalized at both sides by partitions 47 and 48, these beingvented as discussed in connection with the partition 35 found in theheader 32, if desired. Preferably, the partitions 47 and 48 divide thepanels 40 and 41 into a substantially equal number of pipes. The header46 may 'be vented by suitably positioned vents 49.

In order to circulate fluid through the pipes 42 and 43 in the panels 40and 41, respectively, U-shaped sections 50 and 51 are provided to jointhe ends of the pipes 42 and 43, respectively. It will be apparent thatinstead of such U-shaped sections 50 and 51, headers could be providedat this end of the pipes 412 and 43 functioning in the same manner asthe header 33 described in connection with the panel 25. Conversely,U-shaped sections could be substituted for the header 33 in the panel25.

The panels 40 and 41 maybe supported in any desired manner such as bythe brackets 52 and 53, respectively, fastened to the roof 11.

Referring to Figure 4, the header 46 is joined by an elbow pipe section5 to the header 33 at one end, its other end being joined to alongitudinally extending relatively large diameter pipe 55 adjacent tothe side 12. A short section of pipe 55a also joins the upper section ofthe header 32 to the header 46.

Vents 56 release gas from the pipe 55 which extends to a header 57longitudinally positioned in the side 12 across the passage 30, as bestshown in Figures 2, 3 and 6. Joined to the header 57 are a plurality ofpipes 58 each formed with four reverse loops 59 in a vertical planetraversing the passage 30, the other end of the pipes 58 leading to afurther header 60 in the upper portion of the side 13. A connecting tube61 provided with a vent 62 (Figures 1 and 6) joins the header 60 to yetanother header 63, lower in the wall 13 but slightly above the header57, which communicates with a plurality of pipes 64 reversely looped bysections 65 in a similar manner to the pipes 58. Each of the reverselylooped pipes 64 is in a vertical plane and slightly higher than thepipes 59, the pipes 64 and 59 alternating across the passage 30, asclearly shown in Figures 2 and 3. The other ends of the pipes 64communicate with a header 66 (Figures 1. 2 and 6) in the wall 12slightly above the header 60, the header 66 being vented by a vent 67and constituting the outlet for the heated fluid.

Before examining the operation of the present invention, it should beunderstood that when the transfer of heat from the heat source to thefluid proved to be desirably etficient in prior heat transfer systems,there was often excessive localized heating. Such localized heatingresulted in portions of the heated fluid being raised above a selectedtemperature. In instances in which temperature sensitive fluids wereheated, such localized heating deteriorated such fluids.

'In order to achieve both efficient heating and preclude excessivelocalized heating effects, it is necessary to control both the rate ofheat input per unit area of heating surface and the coetficient of heattransfer from the heating surface to the fluid being heated, in relationto the temperature of the fluid being heated.

Referring more particularly to the operation of this embodiment of theinvention, the fluid to be heated by means of the heater 21 enters theheat transfer system at the inlet duct 34- leading to the header 3?;(Figures 2 and 3). The fluid initially flows through only the pipes 26in the lower section of the panel 25 due to the partition 35 (Figure 4).It should be noted that the flow direction of the fluid is shown byarrows in several figures of the drawing. After flowing through thelower pipes 26 around three sides of the enclosure 27, the fluid reachesthe header 33 where it is thoroughly mixed to effectively equalize thetemperature of localized portions of the fluid in the lower pipes 26.From the header 33, the fluid is divided to follow alternate paths, partof the fluid returning to the upper portion of the header 32 through thepipes 26 in the upper section of the panel 25 while the remainder of thefluid is fed through the elbow 54 to the header 46. Due to such dividedfluid flow, it is preferable to have a greater number of the pipes 26 inthe lower section than in the upper section of the panel 25 to equalizethe fluid circulation. Thus, ten pipes are found in the lower sectionand five pipes in the upper section in this instance since there arefive pipes in each section of the panels 40 and 42.

The fluid furnished to 'the header 46 flows through the pipes 43 in thepanel 41 due to the partition 48, such pipes being joined by theU-shaped sections 51. After flowing through the pipes 43, the fluidreturns to the header 46 where it is again thoroughly mixed and flowedthrough the pipes 42 comprising the panel 40. The fluid then returns tobe mixed in the header 46 on the other side of the partition 47, thefluid flowing therefrom to the longitudinally extending pipe 55. Inaddition, the fluid returned to the upper portion of the header 32 flowsthrough the connecting pipe 55a to the header 46 where it joins thefluid flowing to the pipe 55.

The fluid heated in the panels 25, 40 and 41 flows through the pipe 55to the header 57, it being evident that during this flow, the fluid isagain thoroughly mixed to equalize any diflerenc'es in heating in theprevious panels it has traversed. From the header 57, the fluid passesthrough the pipes 58 to the header 60 where it is again thoroughly mixedand flowed through the connecting tube 61 to the header 63. Finally, theheated fluid flows through the pipes 64 to the header 66 and exitstherefrom at the selected temperature.

The pipes in the panels 25, 40 and 41 are, in this embodiment of the'invention, evenly heated by the radiant heat from the source 21 found inthe enclosure 27. In addition, the gases from the enclosure 27 escapethrough the passage 30, as shown by the arrows in Figure 2, and heat byconduction the pipes 58 and 64. It is apparent that this arrangementefliciently uses the heat source 21 since not only does the radiant heatserve to heat the fluid but also the escaping gases give up much oftheir heat to the fluid.

In a typical heating operation which may be performed with the presentinvention, it may be necessary to heat a temperature sensitive liquid toa temperature of 600 F. In this process, it will be assumed that it isundesirable to have any surface in contact with the liquids at atemperature in excess of 640 F., due to the nature of the liquid. Inorder to meet these conditions where the rate of heat transfer to thesurfaces containing the liquid is 16,000 B. t. u.s per square foot hour,the coeflicient of heat transfer from these surfaces to the liquid mustbe at least 400 B. t. u.s per square foot hour F. This is achieved byproviding selected flow velocities of the liquid past the heat transfersurfaces and, at the same time, providing for effective flowdistribution and mixing as described above so that no individual streamof the liquid being heated reaches a bulk temperature appreciably inexcess of the final desired temperature of 600 F. The above is, ofcourse, illustrative of the heating operations which may be carried outin the typical embodiment of the invention herein described.

It is apparent that a heat transfer system constructed in accordancewith the principles of the present invention provides for efficientheating of a fluid without excessive localized heating whichdeteriorates certain fluids.

To this end, provision is made for successive mixing of the fluid fortemperature equalization purposes after it has traversed certainsections of heating pipe.

It will be understood that the above-described embodiments of theinvention are illustrative only and modifications thereof will occur tothose skilled in the art. For example, individual panels may be providedfor each of the interior surfaces of the enclosure 27 having headers ateach end similar to the panel 25 or alternatively, panels similar topanels 40 and 41 may be used for the interior surfaces. Therefore, theinvention is not to be limited to the specific apparatus disclosedherein but is to be defined by the appended claims.

We claim:

1. Heat transfer apparatus for heating fluids comprising an enclosureincluding a plurality of interior surfaces, radiant heating means insaid enclosure, a first panel of first adjacent parallel pipes extendingalong a plurality of said interior surfaces, a first elongated headerlaterally partitioned to provide an inlet section to receive fluid andan outlet section to discharge heated fluid, an inlet pipe communicatingwith the inlet section of the first header, a first group of adjacentfirst pipes communicating at their one ends with the inlet section ofthe first header, a second group of adjacent first pipes communicatingat their one ends with the outlet section of the first header, a secondelongated header communicating with the other ends of said first pipes,a second panel of second adjacent parallel pipes extending along anotherof said interior surfaces, a third elongated header laterallypartitioned to provide inlet and outlet sections, first and secondgroups of adjacent second pipes communicating at their one ends with theinlet and outlet sections of the third header, respectively, meansjoined to the other ends of said second pipes interconnecting said firstand second groups of said second pipes to provide fluid flow in oppositedirections in said -first and second groups of said second pipes, a pipejoining the second header to the inlet section of the third header toprovide fluid flow between said first and second panels, an outlet pipe,and

pipe mean-s providing a direct path for fluid heated in the first panelfrom the outlet section of the first header to the outlet pipe and adirect path for fluid heated in the second panel from the third headerto the outlet pipe, so that a portion of the fluid flowing into the heattransfer apparatus through the inlet pipe is heated in the first paneland another portion of the fluid is heated in the first group of firstpipes in the first panel and in the second panel.

2. Apparatus as defined in claim 1, wherein the first panel extendsalong three vertical interior surfaces of the enclosure, the secondpanel extends along the interior surface defined by the roof, and saidmeans joined to the other ends of said second pipes comprises aplurality of U-shaped sections joining the other ends of said first andsecond groups of said second pipes.

3. Apparatus as defined in claim 1, in which a passage is provided fromsaid enclosure to permit the escape of heated gases produced by saidheating means, third pipes in said passage heated by the escaping gases,and pipe means joining the first header and the third header outletsections to said third pipes to carry the heated fluid from the firstand second panels to said third pipes.

4. Apparatus as defined in claim 1, wherein longitudinally extendingheat absorbing diametrically opposed fins are joined to a plurality ofsaid first and second pipes, the longitudinal edges of the fins inadjacent pipes being closely spaced so that the first and second panelspresent a substantially closed wall to the radiant heating means.

References Cited in the file of this patent UNITED- STATES PATENTS1,082,312 Fouque et al. Dec. 23, 1913 1,814,423 Albert July 14, 19311,890,170 Van Brunt Dec. 6, 1932 2,266,291. Young Dec. 16, 19412,403,017 Nordlund July 2, 1946 2,578,332 Williams Dec. 11, 1951

